Biomolecules

Biomolecules are crucial for understanding how the body functions, representing a vast field of study in organic chemistry.
In a typical semester-long chemistry course (e.g., 1308), there would be extensive study on biomolecules, but in this condensed format, only two days are dedicated to this topic.

Molecules are formed when atoms interact.
The interaction primarily involves valence electrons in the outer shell, which interact to achieve a full shell, leading to atom stabilization.
Bonds formed during this interaction create molecules, specifically large molecules essential for cellular functions.

Molecules are classified into two main categories:
- Inorganic Molecules (e.g., acids, salts, and bases).
- Organic Molecules
- Defined as large and complex molecules that mainly consist of carbon and hydrogen atoms.
- Examples: Those that make up the body's biochemical structure, referred to as biomolecules.

Biomolecules are a subset of organic molecules that specifically impact biological processes.
The four primary categories of biomolecules in the human body are:
1. Carbohydrates
2. Lipids
3. Proteins
4. Nucleic Acids (e.g., RNA and DNA)

Sometimes referred to as macromolecules due to their large size (hundreds to tens of thousands of atoms).
Polymers: Large molecules made from repeating subunits called monomers.
- Example: Each monomer can be visualized as a pearl in a pearl necklace, where the entire necklace represents the polymer.

Monosaccharides: The simplest form of carbohydrates (single sugar molecules).
- Examples: Glucose, fructose, and galactose.
- Formula: All have the empirical formula of C₆H₁₂O₆.
Disaccharides: Composed of two monosaccharides.
- Examples:
- Sucrose (glucose + fructose)
- Lactose (glucose + galactose)
- Maltose (two glucose molecules)
Polysaccharides: Composed of multiple monosaccharides.
- Examples:
- Glycogen: Energy storage in animals.
- Starch: Energy storage in plants.
- Cellulose: Structural component of plant cell walls, not digestible by humans (fiber).

Energy Source: Immediate energy provider for cells, primarily in the form of glucose used to produce ATP.
Energy Storage: Stored as glycogen in the liver/muscles for later use.
Structural Roles: Components of cell walls and cellular structures.
Signaling Molecules: Involved in cell signaling processes.

Characteristics of Lipids:
- Composed primarily of carbon, hydrogen, and oxygen but with less oxygen than carbohydrates.
- Nonpolar and hydrophobic (water-fearing).
Types of Lipids:
- Triglycerides: Storage form of energy in adipose tissue; consists of glycerol and three fatty acids.
- Phospholipids: Essential for forming cell membranes; contains glycerol, two fatty acid tails, and a phosphate group.
- Structure: Contains a hydrophilic (water-attracting) head and two hydrophobic tails.
- Steroids: Characterized by a structure of four carbon rings; includes cholesterol, which is vital for cell membranes and steroid hormones (e.g., testosterone, estrogen).

Energy Storage: Long-term energy reserve.
Protection: Provides cushioning for organs.
Cell Membrane Structure: Phospholipids make up the bilayer of cell membranes.
Hormonal Functions: Steroids act as hormones regulating various physiological functions.

Definition: A chemical reaction where two molecules bond together, releasing a water molecule in the process.
Example: Formation of disaccharides and polysaccharides from monosaccharides.

Definition: A reaction that breaks large polymers into smaller units using water.
Example: Digestion of carbohydrates into monosaccharides for absorption in the digestive system.

The understanding of biomolecules is essential to comprehend their roles in life processes, including energy storage, structural integrity, signaling, and metabolism.
Study of these biomolecules not only reflects their chemical properties but also their biological significance. Their interactions and transformations are critical for cellular function and overall health.